Rotary pump, motor, and meter



May 22, 1928.

R. HAAS I ROTARY PUMP, MOTOR, AND METER Filed March 24, 1926 X- Haas Patented May. 22,1928.

UNITED STATES 1,670,681 PATENT ()FFICE.

RUDOLF HAAS, F BADEN-BADE1\T,' GERMANY.

' ROTARY TUMP, MoToR, AND METER.

7 Application filed March 24, 1926, Serial No. 97,117, and in Germany March 30, 1925.

This invention relates to machines (pumps, prime movers or measuring instruments) of the worm and worm wheel type, in which the worm wheel works in a wheel chamber which forms to a certain extent a shunt to the passage through which the driving or driven fluid flows. In such machines, in the event of a more or less considerable portion of the driving or driven fluid escaping l through this shunt owning to the pressure difli'erence existing between the inlet and outlet sides of the machine, losses will be set up in the machine resulting in a reduction in the quantity of fluid pumped, in the power delivered or the number of revolutions indicated, according to whether the machine is a pump, a motor or a measuring device. It is therefore necessary as is well known to provide means for efficiently sealing the wheel chamber from the passage through which the fluid flows.

Accordin 'way by which the wheel chamber communicates with the high pressure side of the passage through which the fluid flows is smaller than that by which the wheel chamber communicates with the low pressure side of the said passage. By this means, in the case of pumps, all impurities, such as fibres, or the 3 like, which may be resent in the fluid being pumped, can only nd their way with difficulty and to a small extent into the wheel chamber, while on the other hand, once they do enter the wheel chamber they are easily 36 discharged therefrom so that any detrimental accumulation in the wheel chamber is prevented. The invention thus renders it possible to employ pumps of the kind referred to for pumping materials which so readily felt up, for example paper pulp or the like.

In a preferred constructional form of theinvention the worm rotates in a bushing which on the high pressure side of the machine is sealed as far as possible from the wheel chamber but on the low pressure side communicates with the wheel chamber by a comparativelylar e passage way.

A constructiona form of the invention is illustrated by way of example in the accompanying drawin applied to a pump of the kind in which t e wormrotates in a bushing which encloses it and having the worm w eel capable. of being inserted and removed from the side without requiring the worm to be removed also. It is to be unto the invention the passagederstood, however, that the inventionis not limited to such a pump but can be applied to other pumps and machines of the kind referred to.

Fig. 1 shows the pump in longitudinal ,9 (Figs. 1, 3) pressing against the cylinder or wall of the cover, and it is provided with a sl t l2. corresponding to the width of the wheel. On the suction side however, it is cut short so that there is left on bothv sides of the wheel afree space for the outlet'of the fibres or the like from the wheel chamber into the suction space. This free space can even-as seen in Fig. 2be made the whole width of the wheel chamber 0, and also the width of the wheel chamber can be made so large that it need not be turned or milled out, whereby naturally the costs of production of the rotary pump are reduced. The bushing f can, of course, be made correspondingly longer to reach up to the wall of the cover 2', in which case according to the invention the slot h is made wider on the suction side than on the pressure side, to allow of effective means of escape for the fibres gr the like which pass into the wheel cham- In pumps or the like which are provided with means for balancing axial pressure discharge, the essential principle of the inventiondifiieult entry and easy exit of the fibresor the likeis provided for the space which exists at the two end faces ofthe worm. By way of example, Fig. 1 shows at k such an end space which for the purpose of balancing the axial thrust on the worm bearings communicates through the drilled hole Z with a similar space m at the other end of the worm. Here the essential feature of the invention applies in that the unavoidable gap between the pressure spaced and the end space is is essentially more closely restricted than that between the end space m and the suction space 6. By these means, fibres and the like, which areforced from the pressure space (1 into it, and are then passed through Z to m, find a free passage at the end faces of the worm, and interruption in the working of the machine is prevented. A I

The packing members on worm and bushing can be formed as desired, for example, cylindrical or flat or in any other way. Figure 1 shows by way of example on the suction side a cylindrical or slightly conical member, which might perhaps more correctly be called a throttle, and on the pressure side a flat packing member arranged against the end face by means of the ring'n. As this is a packing naturally in the course of time a certain wear will take place. In order to provide for this, Washers p to a suitable amount are arranged, which are secured by screws 0 or the like.

The essential principle of the invention is further concerned with the formation of the packing members themselves. If one considers two ring washers set face to face (or also two ring washers set one within the other) stray pieces of fibre or the like become caught between them, and if notsometimes because of a very high pressure difference between the pressure space (i of the pump and the end space k of the worma very strong flow of current axially to the direction of rotation occurs, which sweeps away the fibres. But usually there is not a sufiiciently high difference of pressure available. In this case, according to the invention, the packing members are so formed on both sides that the stray fibres which lodge between them, escape by a proportionally short path. This can be effected in the use of a flat packing member, for example, in that the ring it does not contact over its whole area with the worm, but only with a proportionally smaller projecting wall 9',

which is eccentrically disposed (Fig. 4). It

may be observed that according to this arrangement the relative motion of the worm face against the ring q opens a free path once each revolution. In Fig. 5 is illustrated another form in which the projecting'wall g on the ring n is made in the form of a square. Of course, other desired formations can be used; and the employment according to requirements of cylindrical and other packing members is possible. Further also, the eflfect which is produced in the constructional forms according to Figs. 4 and 5 by the onesided construction of the rings n or n, can also be secured by the corresponding conformation of the worm packing washer, or also of the two co-operat-ing washers.

Pumps or the like which only work with a small pressure difierence, a throttling such as shown in Fig. 1 between the spaces m and e may be entirely dispensed with, so that the end spaces of the worm are under'the same pressure as exists at the suction side of the pump.

I claim:

1. A machine of the worm and worm wheel type, comprising in combination a casing having a low pressure chamber and a high pressure chamber, a worm in said casing, a. wheel chamber provided on said casing, a worm wheel in said wheel chamber, said worm wheel being adapted tocoact with said worm, a small passage for establishing restricted communication between said wheel chamber and said high pressure chamber and a large passage for establishing free communication between the wheel chamber and the low pressure chamber, as and for the purposes set forth.

2. A machine of the worm and worm wheel type, comprising in combination a casing having a low pressure chamber and a high pressure chamber, a bush arranged in said casing, a worm in said bush, provided on said casing, a worm wheel in said wheel chamber, said worm wheel being adapted to coact with said worm, a small passage for establishing restricted communication between said wheel chamber and said high pressure chamber, said passage consisting in a slot in the bush through which the worm wheel is passed for engaging the worm and a large passage for establishing free communication between the wheel chamber and the low pressure chamber, as and for the purposes set forth.

3. A machine of the worm and worm wheel type, as set forth in claim 1, having a cavity provided at each end of the worm and means for establishing communication between the cavity at the high pressure end of the low pressure end of the worm' and means 7 for establishing communication between the cavity at the high pressure end ofthe worm and the cavity at the low pressure end of the worm, as and for the purposes set forth. I

5. A machine of the wormand worm wheel type, comprising in combination a casing having a low pressure chamber and a high pressure chamber, a bush arranged in said casing, a worm in said bush, packing means provided between the end of the worm and the wall of the high pressure chamber,

said packing means comprisinga packing ring provided on said wall and having a shape such that its face coacts with the end of the worm only over part of the area thereof, means for adjusting said packing ring with respect to the end of the worm, a wheel chamber provided on said casing, a worm: wheel in sald wheel chamber, said worm through which the worm wheel is passed for engaging the worm and a large passage for establishing free communication between the wheel chamber and the low pressure chamber. as and for the purposes set forth.

6. A. machine of the worm and worm wheel type, as set forth in claim 5, and having the packing ring arranged eccentrically with respect to the cud of the worm, as and for the purposes set forth.

In testimony whereof I have signed my name to this specification.

RUDOLF HAAS. 

